The field of this disclosure relates to imaging and collection devices and in particular to methods and devices for illumination, collection and imaging for optical code reading and other data and image capture devices.
Image capture and other data reading devices are used to read optical codes, acquire data, and capture a variety of images. One common data acquisition device is an optical code reader. Optical codes typically comprise a pattern of dark elements and light spaces. There are various types of optical codes, including 1-D codes (such as UPC and EAN/JAN barcodes) and 2-D codes (such as PDF-417 and Maxicode). For convenience, some embodiments are described herein with reference to capture of 1-D barcodes. However, the embodiments may also be useful for other optical codes and symbols as well as other images such as fingerprint capture, and nothing herein should be construed as limiting this disclosure to optical codes or particular types of codes.
One type of data reader is an imaging reader that employs an imaging device or sensor array, such as a CCD (charge coupled device) or CMOS device. Imaging readers can be configured to read both 1-D and 2-D optical codes, as well as other types of optical codes or symbols and images of other items. When an imaging reader is used to read an optical code, an image of the optical code or portion thereof is focused onto a detector array. Though some imaging readers are capable of using ambient light illumination, an imaging reader typically utilizes a light source to illuminate the item being scanned, to provide the required signal response in the imaging device.
The present inventors have recognized that light from high-intensity illumination can reflect off certain surfaces such as metal cans creating a specular reflection of too high an intensity thereby oversaturating the sensor array resulting in ineffective detection. Thus, the present inventors have identified a need for compensating for this reflection condition to enhance data reader performance.